a) Field of the Disclosure
The present invention relates to an adsorbent to adsorb and absorb carbon dioxide (a greenhouse gas), which is the leading cause of global warming, in order to separate the gas, as well as a method for preparation of a polymer nano-composite material having different radicals or functional groups wherein the material may be used to form the adsorbent reactive with heavy metals in order to absorb and adsorb the same, in turn controlling the heavy metals.
b) Background Art
For reduction and treatment of carbon dioxide, absorption, adsorption, membrane separation, and the like as a separation process after combustion (that is, post-combustion separation) have recently been proposed, while a representative example of a separation process before combustion (that is, pre-combustion separation) may comprise decarbonization.
For such post-combustion separation, an absorption process may include using a liquid amine absorbent to absorb carbon dioxide (hereinafter, referred to as ‘CO2’) and separate the same, heating CO2 chemically bonded to an amine group of the absorbent to desorb the same, thus efficiently separating high concentration CO2. Here, the amine absorbent is usually used together with water and material transfer in a carbon dioxide solution may become a factor. Separation of the carbon dioxide solution requires a large amount of energy, owing to oxidation of the amine used during separation, and an additional purification is therefore necessary. Accordingly, it is considered that the foregoing absorption method is very complicated and requires the highest equipment cost among conventionally available methods for CO2 separation. In addition, the absorption method has difficulties in separating CO2 generated from a small CO2 generation source, although advantageously applied to separation of CO2 from a large capacity CO2 generation source.
For use of a high temperature dried adsorbent, Korean Patent No. 10-0899306 for an invention entitled “Calcium based high temperature CO2 absorbent” capable of directly producing high concentration CO2 during separation of CO2 from a dry absorbent, entails disadvantages such as a high processing temperature and increased loss of the dry absorbent due to abrasion.
Meanwhile, the foregoing adsorption method generally utilizes variation in pressure or temperature, or operates a separating process with simultaneous variation in temperature and pressure. A zeolite molecular sieve, activated carbon or a carbon molecular sieve is generally used as the adsorbent herein. The zeolite molecular sieve has high adsorption efficiency but entails a contamination problem caused by other components contained in a combustible gas. The activated carbon shows a lower adsorption rate than zeolite. For physical adsorption, thermal desorption requires a high temperature and, since the adsorption is executed at a high pressure to improve adsorption effect, entails additional energy costs.
In order to enhance CO2 adsorption and separation efficiencies, conventional methods are generally operated at a high pressure and cannot isolate high concentration CO2 by simple separation, instead, separating the same through multiple processing stages. Since a CO2 adsorption amount of an adsorbent is significantly influenced by temperature, the adsorbent is subjected to cooling before a separating process, so as to produce the adsorbent at a relatively low temperature. Moreover, moisture causing considerable decrease in CO2 adsorption must be removed. Consequently, due to the foregoing operation procedures and restrictions thereof, the adsorption method requires considerable energy costs and entails a difficulty in scale-up.
Furthermore, the membrane separation has problems in that currently available separation membranes are relatively expensive, an expensive pre-treatment apparatus for purifying a combustible gas is required, and other costs, for example, costs for replacement and/or purification of a membrane due to contamination thereof are incurred.